Propeller spinner



' o@ `1, 1946v f PROPELLER SPINNER l Filed Aug. n2s, 1943A 3Sheets-Sheet-1 F. M; OWNER 2,408,677

Oct. 1, 1946'.

F. M. wNER 2,408,677

' PROPELLER SPINNER .Filed Aug. 25, 194:5 s sheets-sheet s mi ifm fPatented Oct. 1, 1946 PROPELLER SPINNER Frank Morgan'Owner, Bristol,England, assignor, by mesne assignments, to Rotol Limited,

f Y Gloucester, England Application August 23, 1943, Serial'No. 499,674-K `rIn Great Britain March 23, 1942 This invention concerns' spinnersfor propel- 1ers having variable-pitch bladesand has for its object toprovide a spinner which in conjunction with the propeller blades passingtherethrough will reduce the drag -thereof to a minimum.

The invention is of particularA application to propellers which have cusfitted to thershank ofthe propeller blades to impart an aerofoil formtothe part of the propeller blades adjacent `the spinner. Such propellerssuffer Yfrom the ldisadvantage'that if'the edge of the cuff whichisadjacent the spinner (hereinafter referred to as the lower edge ofthecuif)l is not in close proximity thereto `over the operating range ofthe propeller, that is from the fine pitch position to the featheredposition, the air ceases to flow over the spinner and around thecuifswith a minimum of turbulence and drag. To overcome thisdisadvantage various proposals have been made; in one the lower edge ofthe cuif entered a circular nat-bottomed dished recess formed in thespinner; in another a flat-topped platform was-raised above thespinnerline and over this the lower edge of the cuif rotated, thedistance Abetweerrthe lower edge of thelcuif andthe platform being aminimum and the same for al1 positions of the propeller; p-Theseproposals whilst eliminating the drag produced by poor mating of thecuff and the spinner are unsatisfactory in that the recess or theplatform produces considerable drag itself.

According to the present invention the combination of a propellerspinner and a propeller is characterized in that the spinner contour ismodiedadjacent eachpropeller blade cut-out so that over the operatingrange of the blade that part Vthereof which moves over the spinnersurface is maintained in close proximity thereto.

Preferably the spinner contour is modified by providing a portion raisedabove the spinner line on Vthe Yside of the cut-out vadjacentthe spinnernose, said portion having aY surface of revolution formed by therotation about the longitudinalaxis of the propeller blade of a lineinclined to said axis in the same sense as the spinner line.

The raised portion is faired into the spinner in order to ensure thatstreamline iiow will take place over the spinner and around the base ofthe propellerblade or cuffs. The raised portion is also faired into asurface disposed on the other side of the cut-out, this surfacepreferably being flat and normal to the longitudinal axis of thepropeller blade.

5 claims. (c1. 17o-159) The propeller or the lower edge of the cuff isshaped to similar outline as 'the modied spinner contour and is spacedtherefrom by the smallest permissible amount.

Specific embodiments of the invention will now be described by way ofexample with reference to the accompanying drawings in which:

Figure 1 is a side view of a propeller spinner constructed in accordancewith the invention, part being shown in section.

'Figures 2 and 3 are similar views showing'alternative forms theinvention may take.

Figure 4 is a front elevation of a propeller constructed according tothe invention.

Figure 5 shows the'improved propeller in which the blades '30 t lthroughsleeves I1 into the spinner I0, the nose of which is indicated at I3.

The spinner I0 is adapted for use with a propellerhaving yfour bladeseach of which receives a cuff to impart an aerofoil form to the shank ofthe blade adjacent the spinner. Each blade protrudes through a cut-outIl formed in the wall of the spinner.

In the embodiment shown in Figure 1 a raised convex surface I2 is formedaround the forward half of each cut-out, that is on the side thereofadjacent the spinner nose I3.l This surface extends in a direction awayfrom the spinner nose and around the rear half of the cut-out as a flatsurface I4 normal to the longitudinal axis I5 of the propeller blade.The atand convex surfaces (I4 and I2 respectively) are suitably fairedinto each other and into the spinner surface.

The lower edge I6 rof each cuif I1 is of similar outline lto the spinnercontour, that is the half thereof directed towards the spinner nose isconcave (I 8)v andthe half remote therefrom is flat (I9).

With this construction the lower edge of each cuff can belmadeaccurately tov follow the modified spinnery contour over the'operatingrange of the `propeller (that is between lines a--a and b b) 'but notwhen the propeller blades are moved tothe zero pitch position(indicated'at c-c) when the rear part of each cuff leaves the flatraised surface which is restricted in its dimensions circumferentiallyof the spinner for physical reasons, and the distance between the rearpart of its lower edge I6 and the spinner contour increases withconsequent increase in drag. This is no disadvantage since when theblades assume the negative pitch position it is desirable to have ahighvalue for the drag.

As shown in Figure 2 the convex surface I2 of Figure 1 is replaced by aconic surface 20, the flat surface I4 being retained.

Spinners in which the slope of the spinner line is considerable mayrequire a raised portion of excessive height and accordingly in analternative construction particularly applicable to such spinners andshown in Figure 3, there is provided adjacent the forward half of thecut-outs Il a raised convex surface 2| whilst adjacent the rear half ofthe cut-outs, there is provided a depression having a concave surface22. The surfaces 2I, 22 are faired into each other and into the spinnerwhilst the cuffs are provided with a modified lower edge to match thespinner.

In the construction shown in Figure 3 the surfaces 2I may be replaced bya conc surface and/ or the surface 22 by an inverted conc surface.

2. The combination of a propeller having blades each rotatable about itsown longitudinal axis, and a spinner mounted on said propeller andhaving cut-outs through which the blades project, said spinner beingformed at the Side of each cut-out adjacent the spinner nose with aportion raised above the spinner line and generated as a surface ofrevolution by the rotation about the longitudinal axis of the blade, ofa line inclined to said axis in the same sense as the spinner line, aflattened surface formed on the Aspinner adjacent said raised portion atthe side thereof remote from the spinner nose, said flattened portionbeing normal to the longitudi- It will be observed from the Afiguresthat sur- 'i faces I2, 20, 2l and 22 are generated by aline ofappropriate shape which is rotated about the longitudinal axis I5 of thepropeller and is inclined thereto in the same sense as the spinner line.

The spinner contour may be modiiied as above referred to by a pressingoperation which imparts the desired shape thereto or alternatively thepart of the shape in which it is desired to modify the spinner may beformed and subsequently secured as by riveting or welding to thespinner.

The invention is capable of application to propellers and spinnerswhether cuffs be tted to the propeller blades or not. When the propellerblades are of metal, steel or magnesium, cuffs are normally tted. vIfthe propeller blades are of wood the aerofoil `section of the blade maybe continued so far towards the root of the blade as not to warrant thefitting of cuffs. In the first case referred to, the culic wouldcooperate with the inclined portion of the spinner and in the secondcase referred to the blade itself would perform this function.Accordingly, the term blades as used in the claims refer to propellerblades with or without cuffs, the cuffs being considered to form a partof the blade and not to be a separate entity.

I claim:

1. The combination of a propeller having blades each rotatable about itsown longitudinal axis, and a spinner mounted on said propeller havingcut-outs through which the blades project, said spinner being shaped toprovide on the side of each cut-out adjacent the spinner nose, a portionraised above the general contour line of the spinner, said portionhaving a surface of revolution formed by the rotation about thelongitudinal axis of a blade, of a line inclined to said axis in thesame sense as the spinner line, a flattened portion adjacentveach cutouton the side away from the spinner nose, said flattened portion beingnormal to the longitudinalaxis of the blade and faired into said raisedyportion, said blades having root portions shaped to .overlap said raisedportion in a direction axially of the' blade.

nal axis of the propeller blade, and being merged into the contour ofthe spinner at the end remote from 'the nose thereof by a surfacegenerated by rotation about the longitudinal axis of the 'blade of aline inclined to the spinner axis at an angle greater than the adjacentpart of the spinner surface, said blades being `shaped at their rootportions to overlap said raised portion in a direction axially of theblades.

3. The combination of a propeller having blades each rotatable about itsown longitudinal axis, a spinner mounted on said propeller and havingcut-outs through which the blades project, said spinner being shaped toprovide on the ,side of the cut-out adjacent the spinner nose, a portionraised above the general contour line, said portion .having a surface ofrevolution formed by the rotation about the longitudinal axis of thepropeller-blade of a line inclined to said axis in the same sense as thespinner line, anda cuff secured on each blade adjacent the spinner, saidcuff on each of said blades having a radially inward extension on itsforward 4edge overlapping said raised portion.

4. The combination of a propeller having blades each rotatable about itsown longitudinal axis, a spinner mounted on said propeller and havingcut-outs through which the blades project, and having a portionlsurrounding each cut-out on the side adjacent the spinner nose, saidportion being inclined to the spinner axis at a larger angle than theadjacent part of the spinner and being generated by rotation ofy a lineabout the blade axis, said' blades havingroot ends overlapping theinclined portion of the spinner in a direction axially of the blades.

5. The combination of a propeller having blades each rotatable about itsown longitudinal axis, a spinner mounted on said 4propeller and havingcut-outs through which the bladesrv project, and having a portionsurrounding each cut-out on the side adjacent the spinner nose, saidportion being inclinedvto the spinner axis at a larger angle than theadjacenty part of the spinner and being generated by rotation about'thevblade axis of a straight line inclined to the spinner axis at a larger`angle thany the'adjacent surface of the spinner to provide a conicalsurface, said blades having root portions l*overlapping Ythe in- @linedportions in `directions axiauyof vthe blades.

FRANK MORGAN OWNER.

